Abstract: A method of controlling an oxygen concentration sensor of the type having oxygen pump and sensor cell elements spaced from each other to form a gap or a restricted region both of which are to be placed in some gases containing an oxygen component, and a heater element for heating said oxygen pump and sensor cell elements under energization of a heater current supplied thereto.A pump current is supplied to the oxygen pump element as long as the heater current is supplied to the heater element. However, the initiation of the supply of the pump current is somewhat delayed at the initial stage of the supply of the heater current in order to avoid incorrect operation due to the unstable cool state of the sensor, and to present possible flow of excessive pump current through the pump element which would cause deterioration of the oxygen pump element.

Abstract: An idling speed control system for controlling idling rotational speed of an internal combustion engine. A vacuum-operated actuator having a diaphragm defining a vacuum chamber controls opening and closing of a throttle valve in response to pressures supplied from a change-over control valve to the vacuum chamber. The change-over control valve selectively supplies the vacuum chamber with a first control pressure for opening the throttle valve and a second control pressure for closing same. An electronic control unit generates an on-off control pulse signal having a pulse repetition period corresponding to rotational speed of the engine, one of on-period or off-period of the on-off control pulse signal having a predetermined constant value, and supplies the change-over control valve with the on-off control pulse signal.

Abstract: A method of detecting abnormality in an air-fuel ratio control system for an internal combustion engine, the air-fuel ratio control system having a proportional control valve arranged in an air supply passage for supplying secondary air therethrough to the engine and controlled in response to an output signal from an oxygen concentration sensor arranged in an exhaust system of the engine in a manner such that its valve opening varies in proportion to the magnitude of driving current supplied thereto. A circuit is provided which includes a first transistor, the proportional control valve, and a second transistor arranged in the order mentioned and serially connected with each other between a power source for supplying a predetermined voltage and ground. A value of voltage at a predetermined location in said circuit is sensed while the first and second transistors are in predetermined states of conduction and non-conduction.

Abstract: An idling speed control system for controlling idling rotational speed of an internal combustion engine. A vacuum-operated actuator having a diaphragm defining a vacuum chamber controls opening and closing of a throttle valve in response to pressures suppliedfrom a change-over control valve to the vacuum chamber. The change-over control valve selectively supplies the vacuum chamber with a first control pressure for opening the throttle valve and a second control pressure for closing same. An electronic control unit generates an on-off control pulse signal having a pulse repetition period corresponding to rotational speed of the engine, one of on-period or off-period of the on-off control pulse signal having a predetermined constant value, and supplies the change-over control valve with the on-off control pulse signal.

Abstract: A method for directing an up shift operation for a vehicle having an engine and a manual transmission generates a direction of an up-shift operation when the vehicle speed exceeds a reference speed determined for each gear position. The reference speed of a medium speed gear is varied according to the degree of acceleration at the time of the previous up-shift operation. If the up-shift operation from a low speed gear to the medium speed gear is effected while the vehicle is not accelerating rapidly, the reference speed for an up shift operation from the medium speed gear is lowered. Further, if a cruising state of the vehicle with the medium speed gear after the acceleration is continued for more than a predetermined time period, the reference speed for an up-shift operation from the medium speed gear is also lowered.

Abstract: An idling speed control system for controlling idling rotational speed of an internal combustion engine. A vacuum-operated actuator having a diaphragm defining a vacuum chamber controls opening and closing of a throttle valve in an intake passage of the engine in response to first and second control pressures supplied from a change-over control valve to the vacuum chamber.

Abstract: A mooring system for a tanker comprising an outrigger secured to the tanker, a buoy anchored by chains, and a buoy supporting structure mounted in the outrigger, the buoy supporting structure being connected to or disconnected from the buoy.

Abstract: An idling speed control system for controlling idling rotational speed of an internal combustion engine. A vacuum-operated actuator having a diaphragm defining a vacuum chamber controls opening and closing of a throttle valve in response to first and second control pressures supplied from a change-over control valve to the vacuum chamber. An electronic control unit generates, in response to an on-off control pulse signal having a period corresponding to rotational speed of the engine, one of on-period and off-period of the on-off control pulse signal having a predetermined constant value, and supplies the change-over control valve with the control pulse signal. Preferably, a detector is connected to the electronic control unit for detecting a change in the magnitude of a load on the engine and supplying the electronic control unit with an output signal indicative of the detected change in the load magnitude.

Abstract: An air intake side secondary air supply system for an internal combustion engine is provided with a linear type solenoid valve disposed in an air intake side secondary air supply passage leading to an intake air passage, downstream from the throttle valve. The opening degree of the linear type solenoid valve is controlled continuously by a drive current supplied to the solenoid. The magnitude of the drive current of the solenoid is determined by providing a base value of current which is responsive to a plurality of engine parameters that represent the engine load, and by correcting the base value in accordance with a result of the sensing of concentration of an exhaust gas component.

Abstract: A secondary air control device for an internal combustion engine wherein the secondary air is introduced into the engine intake downstream of the carburetor in response to sudden increases in vacuum, such as upon rapid deceleration of the vehicle and in turn the engine. The device includes detectors and a circuit for controlling the operation of the secondary air control valve which prevent opening of the valve if both the engine temperature is too low and the vehicle transmission is in neutral.

Abstract: Method for controlling an oxygen concentration sensor for sensing an oxygen concentration in an exhaust gas of an internal combustion engine, which sensor includes an oxygen pump element and a heater element, comprises steps for controlling a pump current and a heat current control in response to a result of a detection of engine load. When the engine is operating in a predetermined high load range, the supply of the pump current to the oxygen pump element is stopped, and the heat current to the heater element is reduced when the engine operation in the high load range has continued for more than a predetermined time period. The heater current to the heater element is stopped when the engine load is in a first predetermined load range, and when the engine operation in a second load range which is lighter than the first load range has continued for a predetermined time period.

Abstract: An oxygen concentration sensing device for use in an air-fuel ratio control system of an internal combustion engine includes a pair of solid electrolyte members having oxygen ion permeability which are disposed in the exhaust gas of the engine and arranged to face each other forming a predetermined gap portion between them. Each of the solid electrolyte members is provided with a pair of electrodes. One of the solid electrolyte members is operative as an oxygen pump element when a predetermined constant electric current is supplied across the electrodes thereof. An electric potential developed across the electrodes of the other one of the solid electrolyte members operative as a cell element is supplied to a comparing means in which the input signal from the solid electrolyte member is compared with a predetermined reference potential and a result of comparison is provided as an oxygen concentration detection signal.

Abstract: A vacuum-operated actuator controls opening and closing of a throttle valve in an intake passage of an internal combustion engine in response to pressure in a vacuum chamber thereof. A change-over control valve supplies the vacuum chamber, selectively, with first and second control pressures for opening and closing the throttle valve, respectively. An electronic control unit controls the engine idling rotational speed by generating an on-off control pulse signal having a period corresponding to the engine rotational speed, and supplying the change-over control valve with the on-off control pulse signal to cause same to supply the vacuum chamber with the first or second control pressure.

Abstract: An oxygen concentration sensing device and an air/fuel ratio control system for an internal combustion engine which include a pair of solid electrolyte members having oxygen ion permeability which are arranged to face each other to form a restricted region between them. One of the solid electrolyte members is operative as an oxygen pump element when a pump current is supplied across the electrodes thereof. The sensing device is provided with a current supply part including a limit command circuit which generates a current stop command signal when the magnitude of the pump current exceeds a reference limit level. With the current stop command signal, the supply of the pump current is stopped so as to prevent an overcurrent to the oxygen pump element. The air/fuel ratio control system includes an air/fuel ratio detection part and an air/fuel ratio control part operated by an air/fuel ratio detection signal.